When I was playing my priest, I felt as if I needed my hot keys to stay on top of things. I mapped all my various heals to my number pad, and made targeting macros for people I was responsible for in the raid. I mapped those macros to my function keys and off I went. The only time I'd use my mouse in battle was when I needed to heal someone that I didn't have a macro for. I just don't see how using the mouse would be as fast as using the keyboard. Plus, all that clicking...it would be like Diablo 2 all over again (which wouldn't be the worst thing in the world, now that I think about it).
Anyone else out there use the keyboard method? Are my friends right? Is the mouse the way to go?